As can be seen by reference to the following U.S. Pat. Nos. 2,262,146, 2,939,922, 3,793,489, 4,421,957, and 4,555,598, the prior art is replete with myriad and diverse directional microphone and receiver constructions.
While all of the aforementioned prior art constructions are more than adequate for the basic purpose and function for which they have been specifically designed, these prior art constructions are uniformly deficient with respect to the directivity and sensitivity of their acoustic profile and the results that are generated.
There are a variety of needs for high power acoustic sources having high directivity. These needs include sound sources for remote sensing application where intense acoustic energy directed through the atmosphere can be used to provide information on winds, turbulence, temperature structure and perhaps other parameters.
Another area of use is in the area of communication and crowd control. Highly directed, high level sound can help guide rescue activities or provide emergency information even in noise environments. A third example of an application is use at outdoor concerts to direct the energy towards the audience and minimize annoyance to areas surrounding such events. Modifications to such arenas intended to reduce noise are typically quite expensive and not very effective.
Past devices intended to direct high intensity sound waves are typically large, awkward devices having poor directivity. Approaches used typically include arrays of conventional loudspeakers. Use of large numbers of individual speakers can be quite expensive. For remote sensing applications large horns (e.g., 12 feet in diameter) and dishes have been used to direct sound in the desired direction.
These remote sensing sources produce levels potentially damaging to hearing and the energy has proven annoying to those in surrounding areas at distances greater than one mine. Also, these remote sensing sources are susceptible to problems with rain, snow and hail since large areas of these radiators are exposed. For crowd control and emergency desired communication applications, we know of no sound source that is small enough to be conveniently transported and pointed in the desired direction.
As a consequence of the foregoing situation, there has existed a longstanding need for a generically configured apparatus for both directional sound projectors and receivers which will provide enhanced performance characteristics and the provision of such a construction is a stated objective of the present invention.